(1B) The product $(a+b)(c+d)$
Practice
Expand and simplify.
*Write your answers with powers of $x$ in descending order. $\left(\square x^2 \pm \square x \pm \square\right)$
$\left(x+6\right)\left(x+9\right)$
$\left(x+3\right)\left(x+3\right)$
$\left(x-2\right)\left(-3+x\right)$
$\left(-x+6\right)\left(1+x\right)$
$\left(-2+x\right)\left(-x+3\right)$
$\left(-6+x\right)\left(-x+6\right)$
$\left(7+x\right)\left(9+x\right)$
$\left(4+x\right)\left(8-x\right)$
$\left(-3x+5\right)\left(-2x+7\right)$
$\left(x-5\right)\left(5x-1\right)$
$\left(7x+2\right)\left(4+x\right)$
$\left(x-8\right)\left(1-8x\right)$
$\left(2-7x\right)\left(x-7\right)$
$\left(4+x\right)\left(x-9\right)$
$\left(3+x\right)\left(7+4x\right)$
$\left(1+2x\right)\left(3-x\right)$